Thin-Section CT in the Categorization and Management of Pulmonary Fibrosis including Recently Defined Progressive Pulmonary Fibrosis.

While idiopathic pulmonary fibrosis (IPF) is the most common type of fibrotic lung disease, there are numerous other causes of pulmonary fibrosis that are often characterized by lung injury and inflammation. Although often gradually progressive and responsive to immune modulation, some cases may progress rapidly with reduced survival rates (similar to IPF) and with imaging features that overlap with IPF, including usual interstitial pneumonia (UIP)-pattern disease characterized by peripheral and basilar predominant reticulation, honeycombing, and traction bronchiectasis or bronchiolectasis. Recently, the term progressive pulmonary fibrosis has been used to describe non-IPF lung disease that over the course of a year demonstrates clinical, physiologic, and/or radiologic progression and may be treated with antifibrotic therapy. As such, appropriate categorization of the patient with fibrosis has implications for therapy and prognosis and may be facilitated by considering the following categories: (a) radiologic UIP pattern and IPF diagnosis, (b) radiologic UIP pattern and non-IPF diagnosis, and (c) radiologic non-UIP pattern and non-IPF diagnosis. By noting increasing fibrosis, the radiologist contributes to the selection of patients in which therapy with antifibrotics can improve survival. As the radiologist may be first to identify developing fibrosis and overall progression, this article reviews imaging features of pulmonary fibrosis and their significance in non-IPF-pattern fibrosis, progressive pulmonary fibrosis, and implications for therapy. Keywords: Idiopathic Pulmonary Fibrosis, Progressive Pulmonary Fibrosis, Thin-Section CT, Usual Interstitial Pneumonia © RSNA, 2024.

Back to the future: sagittal CT in the evaluation of COPD.

OBJECTIVES: To identify features of obstructive airway disease on sagittal reconstruction, compare the accuracy of findings to traditional imaging characteristics of COPD, and determine the fraction of additional cases identified using new characteristics. METHODS: The study was approved by the centre's Institutional Review Board and is HIPAA compliant. Two hundred sixteen patients with HRCT and spirometry within a 3-month window were included. Four radiologists evaluated each HRCT for traditional characteristics of COPD and new quantitative and qualitative features of obstruction on axial and sagittal reconstructions. Imaging characteristics were assessed for correlation with the spirometric diagnosis of obstructive airway disease. RESULTS: Quantitative and qualitative findings on sagittal reconstruction are highly specific for COPD (specificity >90 %). Features of hyperinflation on sagittal reconstruction are more accurate predictors of obstruction than traditional axial measures, with greater interobserver reliability (hyperinflation left hemidiaphragm: accuracy: 70.08 % ± 2.49 %; kappa: 0.511 versus traditional measures: accuracy: 62.00 % ± 5.38 %; kappa: 0.407). Sagittal reconstruction identified 27-70 % more patients with COPD than traditional axial findings (p < 0.05). CONCLUSIONS: Analysis of sagittal reconstruction enables greater accuracy and specificity in the diagnosis of obstructive airway disease compared to traditional measures on axial imaging. Use of sagittal reconstructions can help identify up to 70 % more patients with COPD than traditional imaging findings alone. KEY POINTS: • HRCT sagittal reconstruction is useful in the evaluation of obstructive lung disease. • Findings on sagittal reconstructions allow physicians to more accurately diagnose COPD. • Routine use of sagittal reconstructions increases the sensitivity for diagnosing COPD.

Significance of ground-glass opacity on HRCT in long-term follow-up of patients with systemic sclerosis.

Despite little supportive evidence, ground-glass opacity at high-resolution computed tomography, without other signs of fibrosis, has been equated with potentially reversible disease, and in systemic sclerosis, frequently prompts aggressive anti-inflammatory treatment to prevent pulmonary fibrosis. Our study evaluates ground-glass opacity on sequential high-resolution computed tomography in 41 patients with systemic sclerosis over a mean follow-up period of 27 months (r6 to 60 mo). Ground-glass opacity was the most common imaging finding, present in 66%, and usually associated with other signs of interstitial disease, including nonfibrotic interstitial opacities in 27% and fibrotic interstitial opacities in 32%. Improvement was only documented in 2(5%) patients with ground glass and nonfibrotic interstitial opacities. In systemic sclerosis, ground-glass opacity is most commonly associated with irreversible disease. Disease progression or improvement could not be predicted by the presence of ground-glass opacity.

Pulmonary complications of transplantation: radiographic considerations.

The aim of this article is to clarify radiographic definitions associated with common parenchymal patterns encountered in the transplant population and to discuss the most common pathologic causes responsible for each pattern. The article also touches on radiographic findings signifying complications of other intrathoracic structures, including the airways, pleural space, and mediastinum.

Adjacent parenchymal abnormalities in peripheral bronchogenic carcinoma: correlation of thin-section CT with histology.

Our purpose is to correlate thin section CT of peripheral bronchogenic carcinomas with histologically detected lymphatic or vascular invasion. Retrospective 3-year database search revealed 186 surgical resections for primary bronchogenic carcinoma, of which 58 had available preoperative imaging performed at our institution. Cases with prior surgery, nonconfirmatory pathology, remote imaging, or central location were excluded, resulting in a study population of 42 patients, 25 men, 17 women, with a mean age of 69 years. Imaging with 1-3 mm collimation was performed within a mean of 32 days prior to surgery. Histologic diagnoses included adenocarcinoma (n = 24, 57%), squamous cell carcinoma (n = 13, 31%), large cell carcinoma (n = 4, 10%), and small cell carcinoma (n = 1, 2%), with a mean tumor size of 27 mm. Three radiologists blindly and independently recorded bronchovascular thickening, septal and nonseptal opacities, and the extent of each beyond tumor margins: 1) <5 mm, 2) 5-10 mm, and 3) >10 mm. Lymphangio-invasion was correlated with imaging findings, tumor size, and histology. Adjacent parenchymal abnormalities were recorded in 40 (95%) of 42 masses, with isolated nonseptal opacities representing the most frequent abnormality in 21 (50%), followed by bronchovascular thickening in 16 (38%), and septal opacities in 12 (29%). Lymphangio-invasion was present in 16 (38%) of cases. The frequency of lymphangio-invasion was highest (53%) in cases with 2 or more positive findings, and extension beyond 10mm from the tumor margin. This trend did not achieve statistical significance by ROC analysis. Lymphangio-invasion was positively correlated with tumor size, P =.03, but not histology.In conclusion, parenchymal abnormalities beyond tumor margins shown by CT may be due to lymphangio-invasion but imaging findings did not reliably distinguish cases with and without lymphangio-invasion.

Widespread ground-glass opacity of the lung in consecutive patients undergoing CT: Does lobular distribution assist diagnosis?

OBJECTIVE: Our purpose was to establish the most frequent diagnoses associated with widespread ground-glass opacity on CT and to determine if the distribution of ground-glass opacity at a lobular level affects the likelihood of a given diagnosis. MATERIALS AND METHODS: A retrospective search of our department's CT database from January 1998 through December 2000 revealed 153 cases of ground-glass opacity. Patients evaluated using bronchoscopy or open biopsy within 30 days (mean, 6.9 days) of imaging with ground-glass opacity as the predominant high-resolution CT finding were selected. There were 21 men and 16 women with a mean age of 51.4 years. Two chest radiologists, unaware of the clinical diagnoses, independently recorded lobular distributions. Consensus interpretation was used for discrepancies. Primary distributions were recorded as lobular (geographic ground-glass opacity marginated by septal anatomy), centrilobular (ground-glass opacity related to bronchovascular anatomy), or random. RESULTS: Infectious and other histologic diagnoses fell into four diagnostic groups: atypical pneumonia, chronic infiltrative interstitial disease, acute air-space filling, and drug toxicity. Ground-glass opacity was most frequently associated with acute atypical pneumonia (n = 12, 32%), chronic infiltrative disease (n = 10, 27%), acute air-space filling (n = 6, 16%), and drug toxicity (n = 4, 11%). In five patients, a definitive diagnosis was not established. Ground-glass opacity was most commonly randomly distributed (n = 16, 43%), followed by lobular (n = 15, 41%) and centrilobular (n = 6, 16%) distributions. Distribution did not correlate with diagnostic group. CONCLUSION: In unselected cases of ground-glass opacity evaluated at a tertiary institution, atypical infection and chronic infiltrative interstitial disease accounted for 59% of diagnoses. Distribution at a lobular level did not differentiate underlying causes.

Spectrum of CT findings in nosocomial Pseudomonas aeruginosa pneumonia.

The purpose of this study was to evaluate CT findings in nosocomial Pseudomonas aeruginosa Pneumonia (PAP) and to compare features of PAP in patients with isolated P. aeruginosa cultures and those with coexistent infections. A retrospective database search revealed 28 patients with nosocomial PAP (12 men, 16 women; mean age, 57 years) in which thoracic CT had been performed within a mean of 1.7 days from the time of respiratory culture. Two chest radiologists blinded to culture data performed a consensus reading noting distribution and pattern of consolidation, ground-glass opacity, nodules, peribronchial infiltration, necrosis, effusions, and pleural enhancement. Coexistent respiratory cultures were recorded. Consolidation was present in all patients, involving multiple lobes in 23 (82%) and demonstrating upper zonal involvement in 23 (82%). Nodular features were present in 14 (50%), including tree-in-bud patterns with centrilobular distributions in 9 (64%) and larger, randomly distributed nodules in 5 (36%). Five of five patients with consolidations limited to the lower lung zones had associated upper lung nodules. Ground-glass opacity was seen in nine (31%) and peribronchial infiltration in 16 (57%). Necrosis was present in eight (29%). Thirteen (46%) bilateral and five (18%) unilateral pleural effusions were present with enhancement occurring in two (1%). Coexistent positive respiratory cultures were identified in 13 patients. The distribution of consolidation, frequency and distribution of nodules, and frequency of necrosis did not differ significantly between patients with and without other positive cultures. With CT, PAP most commonly presents with multifocal airspace consolidation. Nodular features were identified in half, with one-third demonstrating tree-in-bud opacities. Unsuspected necrosis occurred in one-third of cases. CT findings in patients with and without other respiratory isolates did not differ in the distribution and frequency of consolidations, nodularity, or necrosis.